The various BM stromal cells secrete factors including interleukin 6 (IL6), RANK ligand (RANKL), insulin-like growth factor 1 (IGF1), tumor necrosis factor alpha (TNFα), vascular endothelial growth factor (VEGF), B cell activating factor (BAFF) and stromal cell-derived factor 1 alpha (SDF1) which are required for normal cell function and exacerbate MM disease progression [79-83]. The gene discussed is TNFSF13B; the disease is Miyoshi myopathy.